The N-Ferno 6871 2-Layer Winter Hard Hat Liner w/ Mouthpiece Kit includes a winter hard hat liner with 2 layers of insulation and a thermal mouthpiece attachment for full-face coverage. The lightweight thermal liner is shoulder-length to keep head, ears and neck covered and fits comfortably under helmets or hard hats without feeling too bulky. Both the N-Ferno 6852 Hard Hat Thermal Liner and the N-Ferno 6870 Thermal Mouthpiece have a breathable 100% cotton twill outer shell and a soft 100% polyester fleece lining for added comfort and to stand up to tough environments. HARD HAT LINER There are 4 hook & loop straps on the exterior of the liner designed to securely attach to the interior of a hard hat for versatile protection in extreme work environments. This hard hat winter liner contains pockets by the ears designed to hold regular-sized hand warmers (sold separately) to keep ears warm and comfortable in extreme temperatures.